Low Relative Abundances of the Mucolytic Bacterium Akkermansia muciniphila and Bifidobacterium spp. in Feces of Children with Autism

Abstract

Gastrointestinal disturbance is frequently reported for individuals with autism. We used quantitative real-time PCR analysis to quantify fecal bacteria that could influence gastrointestinal health in children with and without autism. Lower relative abundances of Bifidobacteria species and the mucolytic bacterium Akkermansia muciniphila were found in children with autism, the latter suggesting mucus barrier changes.Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder where gastrointestinal (GI) disturbance is commonly reported (11). Evidence is emerging that the profiles of the GI microbiota (8,9,16,22) and fermentation products (2, 28) in individuals with ASD are different from those of the general population. Finegold et al. (9) have reported a relationship between regressive autism and altered GI microbiota. Indeed, the modulation of intestinal microbiota in children with ASD through the use of antibiotics (19) and probiotics such as Lactobacillus plantarum WCSF1 (17) has been shown to improve behavior and bowel health outcomes. In this study, various GI bacteria, including Clostridium spp., members of the Bacteroides fragilis group, Akkermansia muciniphila, and Prevotella species, which are emerging as important markers of GI health, were examined in children with ASD, their siblings, and community controls. We also investigated whether correlations exist between GI microbial abundances and the presence or absence of caregiver-reported functional GI disorders (FGIDs) in children with ASD.The inclusion criteria for participants were as previously described (26). Briefly, fecal samples were collected from children with ASD (n ϭ 23), recruited through Autism SA, who were diagnosed by a multidisciplinary team using the childhood autism rating scale (20) and/or the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) (3). The ASD participants were diagnosed with autistic disorder (n ϭ 17) and Asperger's syndrome (n ϭ 6), and all but three participants were reported to have a regressive form of autism. Children who met the criteria for ASD but presented with a comorbid diagnosis of a chromosomal abnormality were excluded from the study. We also recruited 22 typically developing siblings (SIB) of the ASD cohort as well as 9 unrelated community controls (CON) without a family history of autism as two different control groups. The CON participants were eligible to participate if they did not have a sibling or first cousin with ASD. Participants' caregivers were required to complete a functional gastrointestinal disorder (FGID) questionnaire (21) and a questionnaire that investigated medication use.Fresh fecal specimens were collected from participants over a 48-h period to exclude day-to-day variability. Each bowel movement was collected in a separate bag and frozen immediately in a portable freezer and stored at Ϫ20°C. Specimens were transported to the laboratory in freezers and stored at Ϫ80°C until they were processed. Specimens were defrosted at room temperature, and all processing was...

Autism spectrum disorders and intestinal microbiota

“…22,24 Finally, a novel mucin-degrading bacterium, Akkermansia muciniphila (phylum Verrucomicrobia), was found at a high level in children with AD by Finegold et al 19 Data regarding the gut microbiota are not always consistent, and some studies have described opposing results. 24 Indeed, some authors have found other genera (Sutterella and Desulfovibrio) in association with ASD patients, 19,25,26 and others have reported the absence of clinically meaningful differences in the intestinal microbiota composition of autistic patients.…”

“…22,24 Finally, a novel mucin-degrading bacterium, Akkermansia muciniphila (phylum Verrucomicrobia), was found at a high level in children with AD by Finegold et al 19 Data regarding the gut microbiota are not always consistent, and some studies have described opposing results. 24 Indeed, some authors have found other genera (Sutterella and Desulfovibrio) in association with ASD patients, 19,25,26 and others have reported the absence of clinically meaningful differences in the intestinal microbiota composition of autistic patients. 27,28 Further support for the microbial hypothesis and for a central role for the gut microbiota in AD derives from studies on autistic children who were treated with antibiotics; the results suggest that the clinical symptoms, regarding both gastrointestinal effects and cognitive skills, and the abnormal urinary secretion of certain chemical compounds may improve after antimicrobial treatment.…”

Urinaryp-cresol is elevated in young French children with autism spectrum disorder: a replication study

“…We were interested in contrasting urinary p-cresol levels in autistic and typically developing children because ASD has been associated with enhanced frequencies of (1) excessive gut permeability, reported by at least some (D'Eufemia et al, 1996;De Magistris et al, 2010), though not all studies (Robertson et al, 2008) and (2) gut infection with cresolproducing C. difficile (Finegold et al, 2002;De Angelis et al, 2013;Keşli et al, 2014;Selmer & Andrei, 2001;Wang et al, 2011). Our initial study reported significantly elevated amounts of urinary p-cresol in 59 Italian ASD children compared with 59 age-and sex-matched controls (p50.05) (Altieri et al, 2011).…”

Does the Human Gut Microbiota Contribute to the Etiology of Autism Spectrum Disorders?

“…Total short-chain fatty acid (SCFA) levels as well as all individual SCFA, with the exception of caproic acid, and branched-chain fatty acids, were elevated in ASD subjects, pointing towards a general increase in microbiota population or activity rather than a major shift in composition, which would more likely lead to more specific changes in fermentation product profiles. The microbiota composition in the same study group had been determined previously [11], but the only significant differences found were a relative decrease in Akkermansia muciniphila and Bifidobacterium spp., with no changes in absolute levels of total bacteria. Also in this latest study [13], fecal levels of phenol and pcresol were determined as markers of amino acid metabolism; however, no differences were found between the study groups.…”

“…A direct comparison between studies is complicated by the fact that different methodologies have been employed and that the study groups may not be directly comparable due to the heterogeneous nature of ASD (for example, ASD subjects with or without GI symptoms). Interestingly, non-autistic siblings of ASD subjects have often been found to have microbiota profiles intermediate between ASD and controls [8,10,11], possibly due to genetic factors, but also possibly a reflection of shared environmental conditions. These studies are further complicated by the fact that autistic subjects often receive frequent medication with antibiotics and are often on special diets or have repetitive dietary behaviors, both of which may alter microbiota composition.…”